Hen egg white lysozyme: carbon-13 nuclear magnetic resonance assignments and dependence of conformational flexibility on inhibitor binding and temperature.

A total of 23 [13C]methyl resonances of lysozyme is firmly or partially assigned. Much of the molecule is shown to be relatively inflexible. Thus, the inter-methyl distance ratios observed in the crystal between Val-93 and Leu-17 are conserved in solution, and also, much of the thermal dependence of the 13C shift is shown to arise from the active site cleft region only and to be substantially removed upon binding of 2-acetamido-2-deoxy-beta-D-glucopyranoside (Glc-N-Ac). (Glc-N-Ac)3 does not significantly affect regions of the molecule other than those affected by Glc-N-Ac. Lysozyme denatures in a single step to give a new, structured state.